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ricko May 24, 2004 4:28 AM

Does anyone have an opinion on the impact of the color depth? Does one notice a difference between 24, 30 and 36 bits, other things equal?

scaramouche May 24, 2004 10:19 AM


Generally speaking, yes, the number of bits can have a huge influence on the quality of your recorded image. Digital imagers function by actually measuring the amount of light falling on each pixel, in each color, and the number of bits correlates with the precision of those measurements. Of course that is only where the process starts so other factors are important, A greater number of bits can be especially visible in the so called dynamic range of images or light to dark ratio and the capabiility for more highlight detail. Careful exposure management is important to exploit the real potential of increased bit depth however.

Hope this helps.

Richard S.

CastleDude May 24, 2004 11:47 AM

Here aresome pictures that show the difference

check out the "Shadow and Dynamic Range" section. These are comparing 22MP sensors.

ricko May 25, 2004 10:26 AM

Thanks, to you both. I guess that with an ordinary pocket-size camera, 24, 30 or 36 bits does´nt make a difference. From what I´ve heard 24 bit is reffered to as "true color", which means that the human eye can´t distuingish any more. Is that true?

scaramouche May 25, 2004 11:02 AM

There is a lot of variability among humans, of course, but what you conclude is correct. However, you are refering to the end result of a very long and complicated calculation process. To get to that end result with best quality values you need to capture more data than that from your subject to account for the variations in brightness range, maintain color fidelity, etc. I believe that most pocket cameras today work with at least 12 bits of data per color which is useful. the Sony cameras, I believe, are all using at least 14 bits which would give better end results, especially color fidelity. I definitely would not go with any camera which captured only 8 bits per channel, if such is still around.

Hope this helps.

Richard S.

LTBerry May 26, 2004 3:58 PM

When you have 8 bits per channel x 3 channels (R,G,B) you get 24-bit color. This is about equal to the range of color the human eye can see. Also, all printers print in 8 bits per pixel. Most cameras shoot in the 12-14 bit range then convert down to 8 bpp for the jpg. If you shoot in RAW, most raw converters will let you convert to 8 bpp or 16 bpp. The main advantage of working in 16 bit per pixel (48 bit color) is when you need to make adjustments to the brightness, contrast, colors, etc you will not get banding of colors in your image. You can also see this by the "combing' effect in your histogram.Also you will get more dynamic range and details in the shadows. So of you shoot in RAW or use a scanner, to get the best quality, you should capture and work in 16 bit mode, do all your adjustments, then convert down to 8bpp for the final, printer-ready product.

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